ThumbGate

Pre-action gates that stop AI coding agents from repeating known mistakes.

Quick Start

npx thumbgate init

This installs the MCP server and wires it into your agent's tool configuration. No API keys required for the free tier.

Or install globally:

npm install -g thumbgate
thumbgate init

MCP Configuration

Add to your agent's MCP config (e.g., claude_desktop_config.json or .cursor/mcp.json):

{
  "mcpServers": {
    "thumbgate": {
      "command": "npx",
      "args": ["-y", "thumbgate"]
    }
  }
}

How It Works

Feedback Capture

When an agent action succeeds or fails, capture structured feedback:

• Thumbs up: Records what worked, tags it, and stores it as a reusable pattern.
• Thumbs down: Records the failure context, what went wrong, and what to change. Repeated failures auto-promote into prevention rules.

Prevention Rules

After a failure pattern repeats (default: 2 occurrences), ThumbGate auto-generates a prevention rule. These rules are injected into agent context before every tool call, blocking the known-bad pattern before it executes.

Pre-Action Gates

Gates intercept tool calls via the MCP PreToolUse hook. Each gate checks the proposed action against:

1. Prevention rules generated from past failures
2. Thompson Sampling confidence scores (adaptive sensitivity)
3. LanceDB vector similarity to known-bad patterns

If a match is found, the gate blocks execution and surfaces the prior failure context.

Context Packs

Bounded retrieval of relevant feedback history for the current task. The agent gets exactly the lessons that matter, not the entire history.

MCP Tools Provided

Tool	Description
capture_feedback	Record thumbs-up/down with structured context
search_lessons	Query the lesson DB by keyword or semantic similarity
get_prevention_rules	Retrieve active prevention rules for the current context
session_primer	Get session handoff context (last task, next step, blockers)
export_dpo	Export feedback pairs in DPO training format

Tiers

	Free	Pro	Team
Feedback capture	3/day	Unlimited	Unlimited
Lesson search	5/day	Unlimited	Unlimited
Active gates	5	Unlimited	Unlimited
Dashboard	-	Yes	Yes
DPO export	-	Yes	Yes
Seats	1	1	Per-seat
Price	$0	$19/mo	$49/seat/mo

Start a 7-day free trial of Pro: https://thumbgate-production.up.railway.app/go/pro?utm_source=skill

Compatibility

ThumbGate works with any MCP-compatible agent:

• Cursor
• Codex
• Gemini CLI
• Amp
• OpenCode
• Any agent supporting the Model Context Protocol

Links

• NPM: thumbgate
• Repository: IgorGanapolsky/ThumbGate
• Dashboard: https://thumbgate-production.up.railway.app/dashboard